April 25 letter cites need to assess Anti-Homosexuality Act impacts
Country's president has returned Anti-Homosexuality Act to Parliament
Kakuma and Dadaab refugee camps are located in the country
Bill contains death penalty provision for 'aggravated homosexuality'
'Aggravated homosexuality' would be punishable by death
MPs last month passed Anti-Homosexuality Act
The measure reflects a growing pattern in parts of sub-Saharan Africa to target members of the LGBTQ community
U.S. Rep. Robert Garcia (D-Calif.) among measure's sponsors
Ugandan lawmakers passed anti-homosexuality bill last week
Some lawmakers argue motion threatens freedom of expression
